All times, unless otherwise noted, are UT (subtract four hours and, when appropriate, one calendar day for EDT)

5/1 May Day or Beltane, a cross-quarter day; the Moon is 2 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 16:005/2 Mercury is at perihelion today5/4 Jupiter is 5 degrees north of the Moon at 14:005/6 The peak of the Eta Aquarid meteor shower (20 per hour for northern observers) occurs at 7:00; the Moon is at apogee, subtending 29' from a distance of 404,318 kilometers (231,232 miles), at 10:24; the Lunar X (also known as the Werner or Purbach Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to begin at 19:505/7 First Quarter Moon occurs at 3:155/10 Saturn (magnitude 0.0, apparent size 18.7'') is at opposition at 18:005/11 Mars is 3 degrees north of the Moon at 14:005/12 The Moon is 1.7 degrees north of the first-magnitude star Spica (Alpha Virginis) at 13:005/13 Mercury is at its greatest heliocentric latitude north today; a double Galilean satellite shadow transit begins at 9:24; Mercury is 8 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) at 16:005/14 Saturn is 0.6 degree north of the Moon, with an occultation occurring in Victoria Land (Antarctica), New Zealand, and southern Australia, at 16:00; Full Moon, known as the Milk or Planting Moon, occurs at 19:165/15 Venus is 1.3 degrees south of Uranus at 13:00; asteroid 9 Metis (magnitude 9.6) is at opposition at 14:005/16 Venus is at aphelion today 5/17 A double Galilean satellite shadow transit begins at 21:225/18 The Moon is at perigee, subtending 33' from a distance of 367,102 kilometers (228,107 miles), at 11:575/20 A double Galilean satellite shadow transit begins at 11:595/21 Mars is stationary at 9:00; Last Quarter Moon occurs at 12:595/22 Neptune is 5 degrees south of the Moon at 4:00; the Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to begin at 21:575/24 A possible new meteor shower associated with Comet 209P/LINEAR peaks at 7:00; Uranus is 1.9 degrees south of the Moon at 20:005/25 Mercury is at greatest eastern elongation (23 degrees) at 7:00; Venus is 2 degrees south of the Moon at 16:005/27 A double Galilean satellite shadow transit begins at 14:345/28 New Moon (lunation 1131) occurs at 18:405/31 Mercury is 6 degrees north of the Moon at 16:00; asteroid 15 Eunomia (magnitude 9.5) is at opposition at 18:00

Nicolas Lacaille (1713-1762) and Joseph Lockyer (1836-1920) were born this month.

Nereid, Neptune’s third-largest satellite, was discovered on May 1, 1949 by Gerard Kuiper.

The May 6th peak of the Eta Aquarid meteor shower occurs after the waxing crescent Moon sets and is not compromised by moonlight. Southern hemisphere observers are favored and may see as many as 55 meteors per hour. Eta Aquarid meteors are debris from the famous periodic comet 1P/Halley. A new meteor shower linked to Comet 209P/LINEAR with a radiant between Ursa Major and Camelopardalis and a peak rate of 100 or more meteors per hour may take place on the morning of May 24th. For additional information, see the article on pages 30 to 35 of the May issue of Sky & Telescope.

Information on Iridium flares and passes of the ISS, the Tiangong-1, the USAF’s X-37B, the HST, and other satellites can be found at http://www.heavens-above.com/

The Moon is located in Taurus and is 1.7 days old on May 1st at 0:00 UT. The Moon occults Saturn from part of Antarctica, New Zealand, and southern Australia, on May 14th. The Moon is at its greatest northern declination on May 2nd (+19.0 degrees) and May 30th (+19.0degrees). The Moon is at its greatest its greatest southern declination on May 16th (-19.0 degrees). Longitudinal libration is at maximum (+5.0 degrees) on May 26th and at minimum (-5.8 degrees) on May 12th. Latitudinal libration is at maximum (+6.9 degrees) on May 5th and at minimum (-6.8 degrees) on May 19th (-6.8 degrees). Visit http://saberdoesthes...does-the-stars/ for tips on spotting extreme crescent Moons. Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occ...o/rays/rays.htm

In the evening, Mercury can be seen in the northwest, Mars in the south, Jupiter in the west, and Saturn in the southeast. Mars is located in the southwest, Jupiter in the northwest, and Saturn in the south at midnight. Venus is in the east, Saturn in the southwest, Uranus in the east, and Neptune in the southeast at dawn.

Mercury is at its brightest during the first half of May. It passes three degrees south of the bright open cluster M45 (the Pleiades) on May 7th. The speediest planet is farthest north of the ecliptic on May 13th and reaches greatest eastern elongation on May 25th.

Venus is positioned low in the eastern sky at morning twilight. The brightest planet is situated 1.3 degrees south of Uranus, which is some 9,000 times fainter, on May 15th and two degrees south of the waning crescent Moon on May 25th.

Mars decreases in brightness from magnitude -1.2 to -0.5 and shrinks in apparent diameter from 14.5 to 11.8 arc seconds this month. The north pole of the planet is tilted 25 degrees with respect to the Earth. Retrograde (westward) motion ends on May 21st. Syrtis Major is prominent during the first week of May. Look for Mare Cimmerium and Elysium during the second week of the month. Consult the Mars Profiler at http://www.skyandtel...watching-tools/ to determine which Martian surface features are visible.

Jupiter sets around 1:00 a.m. local time on May 1st and 11:00 p.m. on May 31st. The waxing crescent Moon passes five degrees to the south of Jupiter on May 4th. A shadow transit by Ganymede begins at 10:08 p.m. EDT on the night of May 5th, followed by a transit by Europa at 12:37 a.m. EDT. Double Galilean satellite shadow transits occur on May 13th, May 17th, May 20th, and May 27th. On the evening of May 30th, Callisto is the only one of the Galilean satellites visible from 10:57 p.m. to 12:55 a.m. EDT, since Europa is transiting Jupiter and Io and Ganymede are in occultation. Browse http://www.skyandtel...watching-tools/ in order to determine transit times of Jupiter’s central meridian by the Great Red Spot. That information is also displayed on page 52 of the May issue of Sky & Telescope. Data on the Galilean satellite events is available at http://www.skyandtel...watching-tools/

Saturn reaches opposition on May 10th and is visible for the entire night. On that date, the Ringed Planet shines at magnitude 0.0 and has an apparent equatorial diameter of 18.7 arc seconds. Its rings are inclined by 21.7 degrees and subtend 42.4 arc seconds. At opposition, Saturn is located 15 degrees south of the celestial equator and is 8.90 astronomical units or 74 light-minutes from the Earth. The article on pages 60 to 62 and 51 of the May issue of Astronomy discusses observing Saturn at opposition. Saturn’s variably bright moon Iapetus shines at magnitude 11.7, as it passes north of the planet on the night of May 6th. For further information on Saturn’s satellites, browse http://www.skyandtel...watching-tools/

At the end of the month, Uranus is visible low in the east in Pisces at dawn.

Neptune rises more than an hour earlier than Uranus. It rises three hours before sunrise by the middle of May. The gas giant is positioned between the fourth-magnitude star Lambda Aquarii and the fifth-magnitude star Sigma Aquarii this month.

Comet C/2012 K1 (PanSTARRS) shines at eighth magnitude as it travels south-eastward through Canes Venatici and Ursa Major. The comet passes two degrees north of the eighth-magnitude spiral galaxy M51 on the evening of May 1st. On May 20th, it glides very close to the tenth-magnitude spiral galaxy NGC 3726 in Ursa Major. An ephemeris is available at http://scully.cfa.ha...?d=c&o=CK12K010 and a finder chart on page 50 of the May issue of Sky & Telescope. Visit http://cometchasing.skyhound.com/ for additional information on this and other comets visible during May.

Asteroids 1 Ceres and 4 Vesta head southwestward through northern Virgo. They remain within three degrees of each other throughout the course of the month. The two brightest asteroids lie 15 degrees northeast of Mars. Finder charts can be found at http://d366w3m5tf081..._Vesta_2014.pdf and on page 53 of the May issue of Astronomy. Click on http://www.skyandtel...s-and-vesta-... for more on Ceres and Vesta. The following asteroids brighter than eleventh magnitude reach opposition this month: 9 Metis (magnitude 9.6), 15 Eunomia (magnitude 9.5), 45 Eugenia (magnitude 10.7), and 65 Cybele (magnitude 10.9). Consult http://www.minorplan...2014/index.html for ephemerides on all of these objects. Information on asteroid occultations taking place this month is available at http://www.asteroido.../2014_05_si.htm